The data values in the ASCII file are drawn directly from the netcdf file "daily_aod_metric_2009.cdf" which also contains all related surface and meteorological data relevant to the data product. In addition, hourly and 10-minutely data is available in data files named "hourly_aod_metric_2009.cdf" and "aod_metric_2009.cdf", respectively. In particular, the 10-minutely file contains flags permitting identification of data source (e.g., NIMFR measurement, interpolated, regressions, ...).